U.S. Pat. No. 6,279,470 to Simeray, et al. describes a portable serving system designed especially for “restaurants that provide meals for pick up or delivery.” See Simeray, col. 1, 11. 23-24. The system includes a tray, various dish plates, and a cover. Electric heating may be employed to maintain elevated temperature of food intended to be served at above-ambient temperature. Likewise, electricity may be used to evacuate residual heat from portions of the tray to reduce food temperatures toward ambient.
Another portable food-delivery device is illustrated in U.S. Pat. No. 6,539,846 to Citterio, et al. Pre-filled dishes placed in distinct bays (seats) of a tray contact “thermal energy transfer devices” intended, apparently, either to heat or to cool the dishes. See Citterio, col. 4, 11. 38-44. A person responsible for delivering meals may roll the device on its wheels and access dishes via a door, which otherwise remains closed.
Non-portable food presentation equipment conventionally is dedicated either to heating or to cooling food contained therein. One such mechanism is described in U.S. Patent Application Publication No. 2008/0023462 of Shei, et al. The food-holding unit of FIG. 1, for example, heats multiple food trays, whereas the unit of FIG. 26 refrigerates the trays. Neither unit both heats and cools, however.
U.S. Pat. No. 6,735,971 to Monroe, et al. shows another non-portable food-presentation device in the form of a multi-well serving bar. At with the food-holding unit of the Shei application, the serving bar of the Monroe patent is dedicated either to heating or to cooling all wells. See Monroe, col. 7, 11. 10-22. Further, such dedicated heating or cooling is preferably uniform as to food contained therein rather than individually controlled. See id., col. 1, 11. 19-28. Although the dedicated refrigerated version of the device may incorporate electric heating elements, such elements are used solely “[t]o prevent over-cooling”—rather than to elevate food temperatures above ambient. See id., col. 5, 11. 14-22. The contents of the Simeray, Citterio, and Monroe patents and of the Shei publication are incorporated herein in their entireties by this reference.
Dine-in, self-service restaurants in particular utilize multi-well food bars such as those illustrated in the Monroe patent. Often, however, providing uniform food temperatures from well to well may be undesirable. As but one example, hard tacos typically include heated meat and refrigerated lettuce, cheese, and other substances placed together in an ambient-temperature corn tortilla shell. These components cannot be placed in adjacent wells of a dedicated food-presentation module, as at least one such component will be served at an undesired (and perhaps unsanitary) temperature. Moreover, even placing tortilla shells adjacent either (heated) meat or (refrigerated) vegetables or dairy products would be problematic if the wells are uniformly heated or cooled.
Smaller dine-in establishments, furthermore, if required to purchase two dedicated modules (one for heated foods and a second for refrigerated foods) may resultingly underutilize the modules. This consequence is especially likely when no more than the number of bays in a single module is needed but some bays would need to contain hot food and the others refrigerated food. Eating establishments of all sizes may, from time to time, also desire to switch a bay from heating to cooling (or vice-versa) depending on time of day. For example, a bay heated for purposes of serving hot breakfast food might be best-utilized at lunch to hold refrigerated foodstuffs, an impossibility with a conventional food bar.